Definitions

life-threatening

[lahyf-thret-ning, -thret-n-ing] / ˈlaɪfˌθrɛt nɪŋ, -ˌθrɛt n ɪŋ /

ADJECTIVE

very dangerous

Synonyms

STRONGEST

deadly lethal mortal serious severe

WEAK

capital critical hazardous threatening touch and go unsafe

Antonyms

STRONGEST

harmless invigorating

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Eighteen percent reported that it led to a life-threatening event or required an intervention to prevent permanent harm.

From MarketWatch • Apr. 22, 2026

Two of the doctors failed to properly intervene as a pregnant teenager repeatedly sought care for life-threatening complications, the board found.

From Salon • Apr. 20, 2026

Half of newborns catch the virus, which can cause anything from a mild cold to a life-threatening chest infection because of inflammation in the lungs.

From BBC • Apr. 17, 2026

A puppy is getting a new leash on life after being rescued with life-threatening facial injuries in Pasadena.

From Los Angeles Times • Apr. 7, 2026

That is, perhaps, why they find it difficult to survive in life-threatening situations.

From "Insurgent" by Veronica Roth